post qualifier and template constraint limitation, is there a reason ?

[Jonathan M Davis via Digitalmars-d]

On Saturday, January 17, 2015 08:33:49 deadalnix via Digitalmars-d wrote:
> This is accepted :
> auto fun(T)(T T) inout if(...) { ... }
>
> This is not :
> auto fun(T)(T T) if(...) inout { ... }
>
> Is there a reason ?

Well, inout is part of the signature. It's debatable as to whether the
template constraint is, particularly when you consider that what you're
really dealing with is

template fun(T)
    if(...)
{
    auto fun(T t) inout {...}
}

just with a shorter syntax. And I'd guess that you have trouble remembering
whether the inout goes primarily due to your coding style. I don't think
that I _ever_ put the template constraint on the same line as the signature,
so I've never had any trouble remembering where the function attributes go
in comparison to the template constraint, and it would never have occurred
to me that anyone would have a problem with that.

But in general, I think that having multiple ways to do the same thing needs
a good reason, especially when it means adding a new way to do something,
and I think that the fact that the template constraint isn't really part of
the function signature is a good reason not to allow the function attributes
after it.

- Jonathan M Davis